1. Field of the Invention
The present invention relates to a composite valve used in an air conditioning system with a hot-gas defrosting cycle or the like, and more particularly, to a composite valve formed of a solenoid valve portion and a differential pressure valve portion, and to a composite valve formed of a solenoid valve portion, differential pressure valve portion, and check valve.
2. Description of the Related Art
There is proposed an air conditioning system that uses a high-temperature, high-pressure gaseous refrigerant (hot gas) in a refrigerating cycle, thereby enjoying improved heating start-up ability in the initial stage of air conditioning. A composite valve described in Japanese Patent Application Laid-Open No. 2001-124440 or 2002-115937 may be used in the refrigerating cycle for this air conditioning system.
The conventional composite valve, however, is bulky and complicated in configuration, since it combines a solenoid on-off valve and a differential pressure valve. Thus, its manufacturing man-hour and machining cost tend to increase. According to the one described in Japanese Patent Application Laid-Open No. 2001-124440, moreover, elements that constitute the differential pressure valve are exposed to the outside, so that refrigerant leakages may be caused in some cases.